Esters of silicic acid



Patented Aug. 20, 1929.

MARTIN M'U'LLER-CUNRAJJI, OF

GESELLSHAFT, or FRANKFOBT-ON-THE mm.

LUDWIGSHAIFEN-ON-THE NEH, F HEIDELBERG, GERMANY, ASSIGNORS TO I. G.

-RHINE, AND GRETE LECH- FARBENINDUSTRIE AKTIEN- -MAIN, GERMANY, ACORPORATON OF GER- ESTERS OF SILICIO ACID.

No Drawing. Application filed January 7, 1928,,Seria1 No. 245,258, andin Germany January 18, 1927.

It is already known that esters of silicic acid can be produced fromsilicon tetrachlorid and anhydrous alcohols. This method of production,however, has the drawback 5 of requiring perfectly anhydrous alcohols,because 0therwise,mixtures with compounds richer in silicon are formed,and the yield of pure esters is small. It is therefore necessary todistil the alcohol, for example over metallic calcium, in order toobtain it in a sufficiently anhydrous condition which is a troublesomeoperation.

We have now found that this expensive and tedious operation ofdehydrating the alcohol is avoided, and that an alcohol which is notcompletely dehydrated can be used, by conducting the process in thepresence of inert diluents, such as hydrocarbons. In this manner a goodyield of a product, which is nearly of unitary character and is directlyapplicable to numerous purposes is obtained. The employment of inertdiluents offers great advantages also when working with anhydrousalcohols. For example the methyl 5 ester, which is usually diflicult toprepare,

can be obtained in this manner.

The following example will further illustrate the nature of the saidinvention which however is not limited thereto. The parts 0 are byweight.

Example.

250 parts of silicon tetrachlorid are slowly treated at room temperaturewith 250 parts of ethyl alcohol, of approximately 98 per cent strengthby volume, under conditions excluding moisture, and diluted with fromQOQO to 2300 parts of benzine of low boiling point. After expelling thebenzine on the water bath, the product is distilled, the bulk, 220parts, passing over between and C. Re-fractionation furnishes a productboiling between 162 and 165 centrigrade and containing 13.0 per cent ofsilicon.

What we claim is:

1. The process for the production of esters of ortho silicic acid whichcomprises treating silicon tetrachlorid with an alcohol in the presenceof an inert diluent.

2. The process for the production of silicon 5o tetra-ethylate whichcomprises treatin silicon tetrachlorid with ethyl alcjohol 0 about 98per cent strength diluted with benzine.

In testimony 'whereof'we have hereunto 55 set our hands.

MARTIN MULLER-CUNRADI. GRETE LECHNER.

